The ability to reduce the surface tension of water is of great importance in waterborne coatings, inks, adhesives, and agricultural formulations because decreased surface tension translates to enhanced substrate wetting in actual formulations. Surface tension reduction in water-based systems is generally achieved through the addition of surfactants. Performance attributes resulting from the addition of surfactants include enhanced surface coverage, fewer defects, and more uniform distribution. Equilibrium surface tension performance is important when the system is at rest. However, the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are utilized. Such applications include spraying, rolling and brushing of coatings or spraying of agricultural formulations, or high speed gravure or ink-jet printing. Dynamic surface tension is a fundamental quantity which provides a measure of the ability of a surfactant to reduce surface tension and provide wetting under such high speed application conditions.
Traditional nonionic surfactants such as alkylphenol or alcohol ethoxylates, and ethylene oxide (EO)/propylene oxide (PO) copolymers have excellent equilibrium surface tension performance but are generally characterized as having poor dynamic surface tension reduction. In contrast, certain anionic surfactants such as sodium dialkyl sulfosuccinates can provide good dynamic results, but these are very foamy and impart water sensitivity to the finished coating.
There is a need for a family of surfactants which provide good equilibrium and dynamic surface tension properties, are low-foaming, are liquids at room temperature to facilitate handling, are stable under basic conditions and would be widely accepted in the waterborne coating, ink, adhesive, and agricultural formulation industries.
The importance of reducing equilibrium and dynamic surface tension in applications such as coatings, inks, and agricultural formulations is well-appreciated in the art.
Low dynamic surface tension is of great importance in the application of waterborne coatings. In an article, Schwartz, J. "The Importance of Low Dynamic Surface Tension in Waterborne Coatings", Journal of Coatings Technology, September 1992, there is a discussion of surface tension properties in waterborne coatings and a discussion of dynamic surface tension in such coatings. Equilibrium and dynamic surface tension were evaluated for several surface active agents. It is pointed out that low dynamic surface tension is an important factor in achieving superior film formation in waterborne coatings. Dynamic coating application methods require surfactants with low dynamic surface tensions in order to prevent defects such as retraction, craters, and foam.
Efficient application of agricultural products is also highly dependent on the dynamic surface tension properties of the formulation. In an article, Wirth, W.; Storp, S.; Jacobsen, W. "Mechanisms Controlling Leaf Retention of Agricultural Spray Solutions", Pestic. Sci. 1991, 33, 411-420, the relationship between the dynamic surface tension of agricultural formulations and the ability of these formulations to be retained on a leaf was studied. These workers observed a good correlation between retention values and dynamic surface tension, with more effective retention of formulations exhibiting low dynamic surface tension.
Low dynamic surface tension is also important in high-speed printing as discussed in the article "Using Surfactants to Formulate VOC Compliant Waterbased Inks", Medina, S. W.; Sutovich, M. N. Am. Ink Maker 1994, 72 (2), 32-38. In this article, it is stated that equilibrium surface tensions (ESTs) are pertinent only to ink systems at rest. EST values, however, are not good indicators of performance in the dynamic, high speed printing environment under which the ink is used. Dynamic surface tension is a more appropriate property. This dynamic measurement is an indicator of the ability of the surfactant to migrate to a newly created ink/substrate interface to provide wetting during high speed printing.
U.S. Pat. No. 5,098,478 discloses water-based ink compositions comprising water, a pigment, a nonionic surfactant and a solubilizing agent for the nonionic surfactant. Dynamic surface tension in ink compositions for publication gravure printing must be reduced to a level of about 25 to 40 dynes/cm to assure that printability problems will not be encountered.
U.S. Pat. No. 5,562,762 discloses an aqueous jet ink of water, dissolved dyes and a tertiary amine having two polyethoxylate substituents and that low dynamic surface tension is important in ink jet printing.
Although many monoalkylated aminoalkylpiperazine derivatives have been reported, it has not been recognized these materials possess surface active properties.
U.S. Pat. No. 3,007,929 discloses compounds of the form ##STR2##
where R is a C8 to C16 linear alkyl group. Aqueous solutions of the C12 and C14 derivatives were effective sterilizing and disinfecting agents for food containers and kitchen utensils.
Zagudullin and Baimetov [J. Gen. Chem. USSR (Engl. Transl.) 1991, 61, 889-894; Zh. Obshch. Khim. 1991, 61, 978-985] report the alkylation of aminoethylpiperazine with ethyl chloride, allyl and methallyl chlorides, and chloropropenes. Depending on reaction conditions and the amount of alkylating agent used, mono-, di-, or tri-allyl and -methallyl derivatives can be formed: ##STR3##
where R=H or CH.sub.3. The workers also report the formation of compounds of the form ##STR4##
Alkylated aminoethylpiperazine compounds are said in this article to be important as catalysts in the synthesis of polyurethanes, polyamines, and epoxy resins. They are also said to be useful as selective solvents and as auxiliary agents in the textile industry.
JP 01 38,080 discloses a class of compounds of the structure ##STR5##
where
R.sup.1 can be C3-C8 linear or branched aliphatic, PA1 R.sup.2 and R.sup.3 can be C3-C11 linear or branched aliphatic, PA1 one of R.sup.2 or R.sup.3 must be H or C1-C2, PA1 R.sup.4 is H or C1-C12 linear or branched alkyl, PA1 m and n are each an integer from 0 to 3 with m+n.ltoreq.3, PA1 p is an integer from 2-13. Specifically shown is 1-[3-[4-methyl-1-(3-methylbutyl)pentylamino]propyl]piperazine. These compounds are disclosed as central nervous system agents and insecticides. PA1 an ability to formulate water-borne coatings, inks, and agricultural compositions which may be applied to a variety of substrates with excellent wetting of substrate surfaces including contaminated and low energy surfaces; PA1 an ability to provide a reduction in coating or printing defects such as orange peel and flow/leveling deficiencies; PA1 an ability to produce water-borne coatings and inks which have low volatile organic content, thus making these surfactants environmentally favorable; PA1 an ability to formulate coating and ink compositions capable of high speed application; and PA1 an ability to formulate compositions which retain excellent dynamic surface tension properties under strongly basic, high temperature environments. PA1 an ability to formulate low surface tension aqueous electronics cleaning and processing solutions, including photoresist developer solutions, for PA1 the semiconductor manufacturing industry with good wetting and extremely low foam.